Backlight module and liquid crystal display

ABSTRACT

A light guide assembly, a backlight module and a liquid crystal display (LCD) are provided. The backlight module includes a back plate, light guide plate, an adhesive member and a light source. The light guide plate is disposed on the back plate and includes a first optical surface, a second optical surface and a light-incident surface. The first optical surface is opposite to the second optical surface. The light-incident surface connects the first optical surface and the second optical surface. The first optical surface or the second optical surface of the light guide plate is set with a recess. The adhesive member is disposed in the recess to adhere the light guide plate to the back plate. The light source is disposed on the back plate and emits light toward the light guide plate.

RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 14/987,773, filed on Jan. 5, 2016, which is a continuation-in-partapplication of U.S. application Ser. No. 14/056,964, filed on Oct. 18,2013, now U.S. Pat. No. 9,268,081 which claims priority to TaiwanApplication Serial Number 102125600, filed Jul. 17, 2013. The entiredisclosures of all the above applications are hereby incorporated byreference herein.

BACKGROUND

Field of Invention

The present invention relates to a light source module. Moreparticularly, the present invention relates to a light guide assembly, abacklight module and a liquid crystal display.

Description of Related Art

A backlight module is one of the critical components of a liquid crystaldisplay (LCD). Currently, liquid crystal displays (LCDs) have beenwidely used in portable electronic products with high-growth potentialssuch as cell phones, notebook computers, digital cameras, etc. With thetrend of portable electronic products toward thinness and lightweight,how to reduce the thickness of the backlight module is an object towhich people in the related industries are devoted.

Referring to FIG. 1, FIG. 1 is a schematic cross-sectional view of aconventional backlight module 100. In the design of the conventionalbacklight module 100, for securing a light guide plate 110, a doublefaced adhesive tape 120 is disposed on a bottom surface of a light guideplate 110 to attach the light guide plate 110 to a back plate 130.However, because the double faced adhesive tape 120 itself has athickness, this securing method using the double faced adhesive tape 120is disadvantageous for thinning the backlight module and the LCD.

Hence, there is a need to provide a light guide assembly, a backlightmodule and a LCD to meet the trend of portable electronic products.

SUMMARY

One aspect of the present invention is to provide a light guideassembly, a backlight module and a LCD, in which a recess is disposed onan optical surface of a light guide plate to accommodate an adhesivemember, such that the adhesive member can be adhered simultaneously to abottom surface and a sidewall of the recess, thereby increasing theadhesive strength between a light guide plate and a back plate.

Another aspect of the present invention is to provide a light guideassembly, a backlight module and a LCD, in which a recess is disposed onan optical surface of a light guide plate to accommodate an adhesivemember, thereby reducing the thickness of the backlight module withoutaffecting the function of the backlight module, further reducing theoverall thickness of the LCD to meet the trend of portable electronicproducts.

According to the aforementioned aspects, the present invention providesa backlight module including a back plate, a light guide plate, anadhesive member and a light source. The light guide plate is disposed onthe back plate, in which the light guide plate includes a first opticalsurface, a second optical surface and a light-incident surface. Thesecond optical surface is opposite to the first optical surface. Thelight-incident surface connects the first optical surface and the secondoptical surface. At least one recess is disposed on the first opticalsurface or the second optical surface of the tight guide plate. Theadhesive member is disposed in the recess to adhere the light guideplate to the back plate. The light source is disposed on the back plateto emit light toward the light guide plate.

According to an embodiment of the present invention, the back plate hasa holding surface facing the first optical surface, and the light guideplate is adhered to the holding surface by the adhesive member.

According to an embodiment of the present invention, the backlightmodule further includes a circuit board disposed on the back plate, inwhich the light guide plate is adhered to the circuit board by theadhesive member.

According to an embodiment of the present invention, the backlightmodule further includes a reflecting film disposed on the back plate,wherein the light guide plate is adhered to the reflecting film by theadhesive member.

According to an embodiment of the present invention, the adhesive memberis corresponding to the recess in shape and size.

According to an embodiment of the present invention, a thickness of thelight guide plate is in a range substantially from 0.5 mm to 0.65 mm, adepth of the recess is in a range substantially from 0.05 mm to 0.1 mm,and a thickness of the adhesive member is in a range substantially from0.05 mm to 0.1 mm.

According to an embodiment of the present invention, the recess is in anelongated stripe shape adjacent to the light-incident surface, in whicha longer side of the recess is parallel to the light-incident surface.

According to an embodiment of the present invention, the light guideplate comprises an opposite light incident surface, wherein the oppositelight incident surface is opposite to the light-incident surface, andthe recess is located adjacent to the opposite light incident surface.

According to the aforementioned aspects, the present invention providesa liquid crystal display including a backlight module and a LCD panel.The backlight module includes a back plate, a light guide plate, anadhesive member and a light source. The light guide plate is disposed onthe back plate, in which the light guide plate includes a first opticalsurface, a second optical surface and a light-incident surface. Thesecond optical surface is opposite to the first optical surface. Thelight-incident surface connects the first optical surface and the secondoptical surface. At least one recess is disposed on the first opticalsurface or the second optical surface of the light guide plate. Theadhesive member is disposed in the recess to adhere the light guideplate to the back plate. The light source is disposed on the back plateto emit light toward the light guide plate. The LCD panel disposed abovethe backlight module.

According to the aforementioned aspects, the present invention providesa light guide assembly including a light guide plate and an adhesivemember. The light guide plate includes a first optical surface, a secondoptical surface and a light-incident surface. The second optical surfaceis opposite to the first optical surface. The light-incident surfaceconnects the first optical surface and the second optical surface. Atleast one recess is disposed on the first optical surface or the secondoptical surface of the light guide plate. The adhesive member isdisposed in the recess.

According to an embodiment of the present invention, the light guideplate has a first area and a second area on the two sides of the lightguide plate, in which at least one recess is disposed on the first areaor the second area.

According to an embodiment of the present invention, the light guideplate further has a third area between the first area and the secondarea, in which a surface of the adhesive member and a surface of thethird area are coplanar.

According to an embodiment of the present invention, the light guideplate further has a third area between the first area and the secondarea, in which a surface of the adhesive member and a surface of thethird area are non-coplanar.

These and other features, aspects, and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims.

It is to be understood that both the foregoing general description andthe following detailed description are by examples, and are intended toprovide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the followingdetailed description of the embodiment, with reference made to theaccompanying drawings as follows:

FIG. 1 is a schematic cross-sectional view of a conventional backlightmodule;

FIG. 2 is a schematic cross-sectional view of a backlight moduleaccording to an embodiment of the present invention;

FIG. 3 is a side view of a light guide plate of a backlight moduleaccording to an embodiment of the present invention;

FIG. 4 is a front view of a first optical surface of a light guide plateaccording to an embodiment of the present invention;

FIG. 5 is a schematic cross-sectional view of a liquid crystal displayaccording to an embodiment of the present invention;

FIG. 6-FIG. 9 are schematic cross-sectional views showing liquid crystaldisplays according to other embodiments of the present invention;

FIG. 10 is a schematic structural diagram of a light guide plateaccording to another embodiment of the present invention;

FIG. 11 is a bottom view of the light guide plate according to anotherembodiment of the present invention;

FIG. 12 is a side view of the light guide date according to anotherembodiment of the present invention; and

FIG. 13 is a side view of a liquid crystal display according to anotherembodiment of the present invention.

DETAILED DESCRIPTION

Reference will now be made in detail to the present embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers are used in thedrawings and the description to refer to the same or like parts.

Referring to FIG. 2 and FIG. 3, FIG. 2 is a schematic cross-sectionalview of a backlight module 210 according to an embodiment of the presentinvention, and FIG. 3 is a side view of a light guide plate of thebacklight module 210 according to an embodiment of the presentinvention. In the present embodiment, the backlight module 210 mainlyincludes a back plate 212, a light guide plate 214, an adhesive member216 and a light source 218.

As shown in FIG. 2, the back plate 212 has a holding surface 212 a. Thelight guide plate 214 is disposed on the holding surface 212 a. Thelight guide plate 214 has a light-incident surface 214 b, a firstoptical surface 214 a, a second optical surface 214 d and a surroundingsurface 214 e. The second optical surface 214 d is opposite to the firstoptical surface 214 a. The light-incident surface 214 b extends along athickness direction of the light guide plate 214 to connect the firstoptical surface 214 a and the second optical surface 214 d. Thesurrounding surface 214 e is connected to the light-incident surface 214b. The light-incident surface 214 b and the surrounding surface 214 esurround the first optical surface 214 a and the second optical surface214 d. In other words, the surrounding surface 214 e can be defined as aside surface of the light guide plate 214. The first optical surface 214a faces the holding surface 212 a, i.e., the first optical surface 214 ais a bottom surface of the light guide plate 214. At least one recess isdisposed on the first optical surface 214 a, such as recesses 215 a and215 b. As shown in FIG. 2, the recesses 215 a and 215 b are also locatedon the surrounding surface 214 e of the light guide plate 214. Theadhesive member 216 can be embedded in the recesses 215 a and 215 b, andthe adhesive member 216 may be aligned with the first optical surface214 a or slightly protrude from the first optical surface 214 a.Therefore, the light guide plate 214 can be adhered and fixed in theback plate 212. In one embodiment, the tight guide plate 214 can bedirectly adhered to the holding surface 212 a of the back plate 212. Inother embodiments, the light guide plate 214 can be adhered to othercomponents, such as flexible circuit boards 417 and 517 or reflectingfilms 419 and 519 (as shown in FIG. 6-FIG. 9).

The recesses 215 a and 215 b are preferably disposed at some positionsof the light guide plate 214 without affecting the light extractionefficiency of the light guide plate 214. In one embodiment the adhesivemember 216 is designed corresponding to the recesses 215 a and 215 b inshape and size. In other words, the shapes and sizes of the recesses 215a and 215 b may be designed in accordance with various types of theadhesive member 216 to change their structure designs, and vice versa.

In one embodiment, the backlight module 210 may be an edge-lightingbacklight module. The light source 218 is disposed on the back plate212, and is adjacent to the light-incident surface 214 b of the lightguide plate 214 so as to emit light toward the light-incident surface214 b. In an exemplary example, the light source 218 may include a lightemitting diode (LED). Referring to FIG. 3 and FIG. 4, FIG. 4 is a frontview of the first optical surface 214 a of the light guide plate 214according to an embodiment of the present invention. In one embodiment,the recess 215 a is in an elongated stripe shape located adjacent to thelight-incident surface 214 b, and a longer side of the recess 215 a isparallel to the light-incident surface 214 b. In the present embodiment,the recess 215 a has an opening 215 a′ located at the light-incidentsurface 214 b. As shown in FIG. 3 and FIG. 4, the surrounding surface214 e further includes an opposite light incident surface 214 c. Theopposite light incident surface 214 c and the light-incident surface 214b are on both sides of the light guide plate 214. In one embodiment, therecess 215 b is in an elongated stripe shape located adjacent to theopposite light incident surface 214 c, and a longer side of the recess215 b is parallel to the opposite light incident surface 214 c. In thepresent embodiment, the recess 215 b has an opening 215 b′ located atopposite light incident surface 214 c.

It is noted that the number of the recesses can be adjusted according toactual requirements. Furthermore, the recesses can be disposed on thefirst optical surface 214 a of the light guide plate 214 simultaneouslyadjacent to the light-incident surface 214 b and the opposite lightincident surface 214 c; on four corners of the first optical surface 214a; or on the edge of the first optical surface 214 a. In one embodiment,for matching the component arrangement in the backlight module 210, therecesses can be disposed on the second optical surface 214 d of thelight guide plate 214. In other embodiments, the recesses can bedisposed on the surrounding surface 214 e. As long as not affectinglight emission of the light source 218, any embodiments with recessesdisposed on the first optical surface 214 a, the second optical surface214 d or the surrounding surface 214 e of the light guide plate 214 in abacklight module to accommodate the adhesive member 216 fall into thescope of the present invention.

As shown in FIG. 3, in the present embodiment, the light guide plate 214is a wedge plate structure, i.e., the light guide plate 214 has a firstarea A1 and a second area A2. The first area A1 and the second area A2are on the two sides of the light guide plate 214, and a thickness ofthe first area A1 is larger than a thickness of the second area A2. Inthe present embodiment, the recess may be disposed on the first area A1or the second area A2. In other embodiments, the light guide plate 214may be a flat plate structure, i.e., the thickness of the first area A1and the thickness of the second area A2 are equal.

In one embodiment, the light guide plate 214 has a third area A3 betweenthe first area A1 and the second area A2. When the adhesive member 216is embedded in the recess, a surface of the adhesive member 216 and asurface of the third area A3 may lie in the same plane. In otherembodiments, the surface of the adhesive member 216 and the surface ofthe third area A3 may lie in different planes.

Referring to Table 1 below, Table 1 is a data table of an opticalsimulation result in accordance with an embodiment of the presentinvention. The wedge-shaped light guide plate 214 is used as a testedobject, and the recess 215 a is disposed on the first optical surface214 a and is located adjacent to the light-incident surface 214 b of thelight guide plate 214. The data in Table 1 is obtained by simultaneouslychanging the depth of the recess 215 a and the position of the recess215 a corresponding to an opening of the light source. In the opticalsimulation, a thickness of the light guide plate 214 adjacent to thelight-incident surface 214 b is about 0.65 mm, a length of an elongatededge parallel to the light-incident surface of the light guide plate 214is about 201 mm, and a thickness of the adhesive member 216 is in arange from 0.05 mm to 0.1 mm.

TABLE 1 Data table of an optical simulation result in accordance with anembodiment of the present invention opening of thickness of averagelight source light guide plate recess structure uniformity luminanceeffect 0.59 mm 0.65 mm original structure 75.90% 10854  100% (original(no recess) thickness) 0.59 mm 0.55 mm 201* 1* 0.1 mm 78.96% 9980 91.9%(deduct depth of (The opening of light the recess) source is blocked by0.1 mm.) 0.59 mm 0.6 mm 201* 1* 0.05 mm 77.86% 10500 96.7% (deduct depthof (The opening of light the recess) source is blocked by 0.05 mm.) 0.59mm 0.6 mm 201* 1* 0.05 mm 76.71% 10738 98.9% (deduct depth of (Theopening of light the recess) source is not blocked, and the bottomsurface of the recess is at the same elevation with the bottom surfaceof the light source.) 0.59 mm 0.6 mm 201* 1* 0.05 mm 76.24% 10831 99.8%(deduct depth of (The opening of light the recess) source is notblocked, and the bottom surface of the recess is spaced from the bottomsurface of the light source at about 0.05 mm.)

As shown in Table 1, the luminance (i.e. 10854) emitted by the lightguide plate without recesses (original structure) is used as a standard.When the recess with thickness of 0.05 mm is disposed on the light guideplate without blocking the opening of the light source 218, theluminance emitted by the light guide plate is smaller than the luminanceemitted by the original structure by about 0.2%-1.1%. It can be knownfrom the above that, the light extraction efficiency of the backlightmodule 210 is not affected by deposing the recess 215 a. It is notedthat, the overall thickness of the backlight module 210 can be reducedby 10% by deposing the recess 215 a.

Referring to Table 2 below, Table 2 is a data table of an opticalsimulation result in accordance with another embodiment of the presentinvention. The wedge-shaped light guide plate 214 is used as a testedobject, and the recess 215 b is disposed on the first optical surface214 a and is located adjacent to the opposite light incident surface 214c of the light guide plate 214. The data in Table 2 is obtained bysimultaneously changing the depth of the recess 215 b. In the opticalsimulation, a thickness of the light guide plate 214 adjacent to theopposite light incident surface 214 c is about 0.5 mm, a length of anelongated edge which is parallel to the opposite light incident surfaceof the light guide plate 214 is about 201 mm, and a thickness of theadhesive member 216 is in a range from 0.05 mm to 0.1 mm.

TABLE 2 Data table of an optical simulation result in accordance withanother embodiment of the present invention opening of thickness ofaverage light source light guide plate recess structure uniformityluminance effect 0.59 mm 0.5 mm original structure 75.90% 10854  100%(original (no recess) thickness) 0.59 mm 0.4 mm 201* 1* 0.1 mm 78.33%10929 100.7% (deduct depth of the recess) 0.59 mm 0.45 mm 201* 1* 0.05mm 75.91% 10831 99.79% (deduct depth of the recess)

As shown in Table 2, the luminance (i.e. 10854) emitted by the lightguide plate without recesses (original structure) is used as a standard,the light extraction efficiency of the backlight module 210 is notaffected by deposing the recess 215 b adjacent to the opposite surface214 c of the light guide plate 214. Similarly, the overall thickness ofthe backlight module 210 can be reduced by 10% by deposing the recess215 b.

Therefore, the thickness of the backlight module 210 can be reduced andthe adhesive strength between the light guide plate 214 and the backplate 212 can be enhanced by deposing the recess, such as the recesses215 a and 215 b, on first optical surface 214 a or the second opticalsurface 214 d of the light guide plate 214 to accommodate the adhesivemember 216 and secure the light guide plate 214 in the back plate 212without affecting the function of the backlight module 210.

Referring to FIG. 5, FIG. 5 is a schematic cross-sectional view of aliquid crystal display 300 according to an embodiment of the presentinvention. The liquid crystal display 300 includes a backlight module310 and a LCD panel 320. The LCD panel 320 is disposed above thebacklight module 310. The structure of the backlight module 310 issimilar to that of the backlight module 210. The backlight module 310also includes a back plate 12, a light guide plate 314, an adhesivemember 316 and a light source 318, and uses the recess, such as therecesses 315 a and 315 b, disposed on the first optical surface 314 a ofthe light guide plate 314 to accommodate the adhesive member 316 so asto achieve the same purposes of the aforementioned embodiments, and thusare not described again herein.

In one embodiment, white coverlays 217 and 317 can be disposed under thelight guide plates 214 and 314. The white coverlays 217 and 317 aremainly used to replace white reflectors disposed under light guideplates in conventional backlight modules. Because the thickness of aconventional white reflector is 0.05 mm under the condition ofreflection rate of 83.6%, the thickness of the backlight modules 210 and310 can be further reduced by replacing the respective white reflectorswith the white coverlays 217 and 317. Referring to Table 3, Table 3 is acomparison table between the reflection rate of the white reflector andthat of the white coverlay 217 or 317.

TABLE 3 comparison of reflection rates between white reflector and whitecoverlay sample white reflector white coverlay 1 82.9% 83.03% 2 82.19%84.01% 3 81.7% 83.78% Average 82.06% 83.61%

As shown in Table 3, the white coverlays 217 and 317 used to replace thewhite reflectors not only do not affect the overall light reflectionrate but reduce the thickness of the respective backlight modules.

Referring to FIG. 6 and FIG. 7, FIG. 6 and FIG. 7 are schematiccross-sectional views showing a liquid crystal display 400 according toother embodiments of the present invention. In FIG. 6, the liquidcrystal display 400 includes a backlight module 410 and a LCD panel 420.The LCD panel 420 is disposed above the backlight module 410. Thestructure of the backlight module 410 is similar to the structure of thebacklight module 210. The backlight module 410 includes a back plate412, a light guide plate 414, an adhesive member 416, a flexible circuitboard 417, a light source 418 and a reflecting film 419. The flexiblecircuit board 417 and the reflecting film 419 are disposed under thelight guide plate 414. A recess 415 is disposed on an optical surface414 a facing the reflecting film 419 of the light guide plate 414 foraccommodating the adhesive member 416 to secure the light guide plate414 on the reflecting film 419.

As shown in FIG. 6, the recess 415 is disposed on the light guide plate414 adjacent to the opposite light incident surface. In otherembodiments, as shown in FIG. 7, the recess 415 may be disposed on thelight guide plate 414 adjacent to the light source 418. Therefore, theadhesive member 416 disposed in the recess 415 can secure the lightguide plate 414 on the flexible circuit board 417.

Referring to FIG. 8 and FIG. 9, FIG. 8 and FIG. 9 are schematiccross-sectional views showing a liquid crystal display 500 according toother embodiments of the present invention. In FIG. 8, the liquidcrystal display 500 includes a backlight module 510 and a LCD panel 520.The LCD panel 520 is disposed above the backlight module 510. Thestructure of the backlight module 510 is similar to the structure of thebacklight module 210. The backlight module 510 includes a back plate512, a light guide plate 514, an adhesive member 516, a flexible circuitboard 517, a light source 518 and a reflecting film 519. The flexiblecircuit board 517 is disposed above the light guide plate 514 and thereflecting film 519 is disposed under the light guide plate 514. Arecess 515 is disposed on an optical surface 514 a facing the flexiblecircuit board 517 of the light guide plate 514 for accommodating theadhesive member 516 to secure the light guide plate 514 on the frame ofthe back plate 512.

As shown in FIG. 8, the recess 515 is disposed on the light guide plate514 adjacent to the opposite light incident surface. In otherembodiments, as shown in FIG. 9, the recess 515 may be disposed on thelight guide plate 514 adjacent to the light source 518. Therefore, theadhesive member 516 disposed in the recess 515 can secure the lightguide plate 514 on the flexible circuit board 517.

In the present invention, the light guide plate can be different shapestructure other than the shape shown in previous embodiments. Referringto FIG. 10, FIG. 11 and FIG. 12, FIG. 10, FIG. 11 and FIG. 12 are aschematic structural diagram, a bottom view and a side view of a lightguide plate 600 according to another embodiment of the presentinvention. The light guide plate 600 includes a light-incident surface610, a first optical surface 620, a second optical surface 630 and asurrounding surface 640. The second optical surface 630 is opposite tothe first optical surface 620. The light-incident surface 610 extendsalong a thickness direction of the light guide plate 600 to connect thefirst optical surface 620 and the second optical surface 630. Thesurrounding surface 640 is connected to the light-incident surface 610.The light-incident surface 610 and the surrounding surface 640 surroundthe first optical surface 620 and the second optical surface 630.

Referring to FIG. 10, FIG. 11 and FIG. 12 again, in the presentembodiment, at least one recess 650 is disposed on the surroundingsurface 640 of the light guide plate 600. Moreover, the surroundingsurface 640 includes an opposite light incident surface 642 and pluralside surfaces 644. The side surfaces 644 are located between thelight-incident surface 610 and the opposite light incident surface 642.In one embodiment, the recess 650 is located adjacent to at least one ofthe side surfaces 644. The recess 650 has a first opening 652 and asecond opening 654, in which the first opening 652 is located at the atleast one of the side surfaces 644, and the second opening 654 islocated at the light-incident surface 610. As shown in FIG. 11, in someembodiments, the recess 650 is in an elongated stripe shape, and alonger side of the recess 650 is parallel to the at least one of theside surfaces 644.

Referring to FIG. 13, FIG. 13 is a side view of a liquid crystal display800 according to another embodiment of the present invention. The liquidcrystal display 800 includes a backlight module 700 and a liquid crystaldisplay panel 810. The liquid crystal display panel 810 is disposedabove the backlight module 700. In the present embodiment, the backlightmodule 700 includes a back plate 710, a light source 720, an adhesivemember 730, a reflecting film 740 and the light guide plate 600 as shownin FIG. 10. As shown in FIG. 13, the reflecting file 740 is disposed onthe back plate 710 and the light guide plate 600 is adhered to thereflecting film 740 by the adhesive member 730. The light source 720 isdisposed adjacent to the light-incident surface 610 of the light guideplate 600 to emit light towards the light guide plate 600.

It is noted that, the embodiment shown in FIG. 13 showing that lightguide plate 600 is adhered to the reflecting film 740 by the adhesivemember 730, is merely used as an example for explanation, and otherembodiments of the present invention are not limited thereto. In otherembodiments, the light guide plate 600 can be directly adhered to aholding surface 710 a of the back plate 710, or the light guide plate600 can be adhered to a circuit board, so as to reduce the overallthickness of the backlight module 700 as well as the liquid crystaldisplay 800.

According to the aforementioned embodiments of the present invention,one advantage of the present invention is to dispose a recess on anoptical surface of a light guide plate to accommodate an adhesivemember, thus attaching the adhesive member simultaneously to a bottomsurface and a sidewall of the recess, and increasing the adhesivestrength between a light guide plate and a back plate.

According to the aforementioned embodiments of the present invention,another advantage of the present invention is to dispose a recess on anoptical surface of a light guide plate to accommodate an adhesivemember, thus reducing overall thickness of backlight module withoutaffecting the function of the backlight module. When the mountingtechnology of LED is advanced to decrease the mounting height of theLED, the embodiments of the present invention can be applied to reducethe overall thickness of the backlight module and achieve an object ofthinness and lightweight.

Although the present invention has been described in considerable detailwith reference to certain embodiments thereof, other embodiments arepossible. Therefore, the spirit and scope of the appended claims shouldnot be limited to the description of the embodiments contained herein.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentinvention without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the present inventioncover modifications and variations of this invention provided they fallwithin the scope of the following claims.

What is claimed is:
 1. A backlight module, comprising: a light guideplate comprising: a first optical surface; a second optical surfaceopposite to the first optical surface; a light-incident surfaceextending along a thickness direction of the light guide plate toconnect the first optical surface and the second optical surface; alight source which emits light towards the light guide plate; anadhesive member; and a back plate, wherein the back plate has a holdingsurface facing the first optical surface, and the light guide plate isadhered to the holding surface by the adhesive member; wherein the lightguide plate has a first area, a second area and a third area, whereinthe first area and the second area are on the two sides of the lightguide plate, and the third area is located between the first area andthe second area, wherein a surface of the adhesive member and a surfaceof the third area are coplanar.
 2. A liquid crystal display, comprising:a backlight module of claim 1, and a liquid crystal display paneldisposed above the backlight module.
 3. A backlight module, comprising:a light guide plate, comprising: a first optical surface; a secondoptical surface opposite to the first optical surface; and alight-incident surface extending along a thickness direction of thelight guide plate to connect the first optical surface and the secondoptical surface; wherein at least one recess is disposed on the firstoptical surface or the second optical surface of the light guide plate;a light source which emits light towards the light guide plate; anadhesive member disposed in the recess; and a circuit board, wherein thelight guide plate is adhered to at least one component of the backlightmodule by the adhesive member other than being adhered to the circuitboard by the adhesive member.
 4. The backlight module of claim 3,wherein the recess is adjacent to the light-incident surface, and therecess has an opening which is located at the light incident surface. 5.The backlight module of claim 3, wherein the light guide plate furthercomprises an opposite light incident surface opposite to thelight-incident surface, and the recess is located adjacent to theopposite light incident surface, and the recess has an opening which islocated at the opposite light incident surface.
 6. The backlight moduleof claim 3, wherein the light guide plate further comprises an oppositelight incident surface and a plurality of side surfaces between thelight-incident surface and the opposite light incident surface, and therecess has a first opening and a second opening, wherein the firstopening is located at the at least one of the side surfaces, and thesecond opening is located at the light-incident surface.
 7. Thebacklight module of claim 3, further comprising a back plate, whereinthe back plate has a holding surface facing the first optical surface,and the light guide plate is adhered to the holding surface by theadhesive member.
 8. The backlight module of claim 3, further comprisinga reflecting film, wherein the light guide plate is adhered to thereflecting film by the adhesive member.
 9. A liquid crystal display,comprising: a backlight module of claim 3, and a liquid crystal displaypanel disposed above the backlight module.
 10. A backlight module,comprising: a light guide plate, comprising: a first optical surface; asecond optical surface opposite to the first optical surface; and alight-incident surface extending along a thickness direction of thelight guide plate to connect the first optical surface and the secondoptical surface; a light source which emits light towards the lightguide plate; an adhesive member; and a circuit board, wherein the lightguide plate is adhered to at least one component of the backlight moduleby the adhesive member other than being adhered to the circuit board bythe adhesive member; wherein the light guide plate has a first area, asecond area and a third area, wherein the first area and the second areaare on the two sides of the light guide plate, and the third area islocated between the first area and the second area, wherein a surface ofthe adhesive member and a surface of the third area are coplanar.
 11. Aliquid crystal display, comprising: a backlight module of claim 10, anda liquid crystal display panel disposed above the backlight module.